published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

This study examines the waste of cotton gins as a potential alternative energy source, on account of its heat content, availability, and low emission rates. To confirm that this potential energy source meets minimum industrial fuel standards, this research has carried out an investigation of some important physical characteristics and toxic element analysis of cotton gin waste. Using cotton gin waste as fuel is an attractive solution to the problems of disposing of a surplus agricultural waste as well as supplementing fuel must meet both environmental emission standards and industrial fuel standards, the physical and chemical characteristics of cotton gin waste and its toxic element concentrations are important for its objective evaluation as a fuel. Constituent components, moisture contents, and ash contents of four separate parts of cotton gin waste were determined and evaluated closely following the American Society for Testing and Materials (ASTM) test methods. The three most toxic heavy metals, Arsenic (As), Chromium (Cr), and Lead (Pb), chosen for quantitative analysis were determined by using an inductively coupled plasma atomic emission spectrometry and a microwave oven sample digestion method.

The Oregon State University (OSU), Hydro Mechanical Fuel test Facility (HMFTF) is designed to hydro-mechanically test prototypical plate type fuel. OSU's fuel test program is a part of the Global Threat Reduction Initiative (GTRI), formerly known as the Reduced Enrichment for Research and Test Reactor program. One of the GTRI's goals is to convert all civilian research, and test reactors in the United State from highly enriched uranium (HEU) to a low enriched uranium (LEU) fuel in an effort to reduce nuclear proliferation. An analytical model has been developed and is described in detail which complements the experimental work being performed by the OSU HMFTF, and advances the science of hydro-mechanics. This study investigates two methods for determining the critical flow velocity for a pair of laminated plates. The objective is accomplished by incorporating a flexural rigidity term into the formulation of critical flow velocity originally derived by Miller, and employing sandwich structure theory to determine the rigidity term. The final outcome of this study results in the developing of a single equation for each of three different edge boundary conditions which reliably and comprehensively predicts the onset of plate collapse. The two models developed and presented, are termed the monocoque analogy and the ideal laminate model. / Graduation date: 2013

Uppsatsen behandlar olika aspekter av skogsbränslemarknaden mot bakgrund av biobränslets ökande betydelse i den svenska energiförsörjningen. Biobränslets andel av den totala svenska energitillförseln har ökat stadigt de senaste två decennierna. Ökningen hänger mycket samman med att värmesektorn, och då i främsta hand värmeverken, har ökat användningen av biobränslen och en stor andel av denna utgörs av skogsbränslen, dvs avverkningsrester och biprodukter från skogsindustrin. Skatter på fossila bränslen har varit en viktig drivkraft. Uppsatsen gör en beskrivning av vilka aktörerna på skogsbränslemarknaden är och hur kedjan från skogen till slutanvändare ser ut. Analysen är baserad på egna intervjuer av såväl säljare och användare av skogbränslen men också på sekundärdata av olika slag. Statistiken är bristfällig. Trenden för priser på skogsbränslen är uppåtgående och såväl säljare som användare väntar sig att priserna ska fortsätta upp i reala termer. Skogsbränslemarknaden ser ut att vara en fungerande (effektiv) marknad trots att den är förhållandevis ny och stadd i kraftig förändring. Många aktörer gör att konkurrensen är påtaglig i alla led. Det finns konkurrens både på säljarsidan och användarsidan. Dessutom sker viss import och export. Import av pellets är särskilt viktig. Men det sker också import av flis och samt rundved (för flisning). Det finns ett element av regionalisering förknippad med höga transportkostnader för lastbilstransporter. / I discuss various aspects of the market for wood fuels against the background of the increasing importance of bio fuels in the Swedish energy system. The use of bio fuels as a share of total energy supply in Sweden has increased considerably during the last couple of decades. Taxes on fossil fuels explain the increase in use of bio energy. It is district heating (fjärrvärme) which is the main user of wood fuels (outside the paper and sawmill industries themselves). The supply chain from the cutting of logs to the end user is described. I base the description/analysis on interviews with suppliers and users of wood fuels as well as secondary sources. Statistics on wood fuels are generally deficient. Prices on wood fuels have increased in real terms and market actors (producers as well as users) expect prices to continue to increase in the medium term. The market for wood fuels appears to be an efficient one despite the lack of standards and the despite the fact that it is a “new” market. There are a fairly large number of producers as well as users and there are no barriers to entry. The market is also “contestable” in the sense that wood fuels are imported. There is though an element of regionalisation of the wood fuel market due to high transportation costs.

<p>Uppsatsen behandlar olika aspekter av skogsbränslemarknaden mot bakgrund av biobränslets ökande betydelse i den svenska energiförsörjningen. Biobränslets andel av den totala svenska energitillförseln har ökat stadigt de senaste två decennierna. Ökningen hänger mycket samman med att värmesektorn, och då i främsta hand värmeverken, har ökat användningen av biobränslen och en stor andel av denna utgörs av skogsbränslen, dvs avverkningsrester och biprodukter från skogsindustrin. Skatter på fossila bränslen har varit en viktig drivkraft.</p><p>Uppsatsen gör en beskrivning av vilka aktörerna på skogsbränslemarknaden är och hur kedjan från skogen till slutanvändare ser ut. Analysen är baserad på egna intervjuer av såväl säljare och användare av skogbränslen men också på sekundärdata av olika slag. Statistiken är bristfällig. Trenden för priser på skogsbränslen är uppåtgående och såväl säljare som användare väntar sig att priserna ska fortsätta upp i reala termer.</p><p>Skogsbränslemarknaden ser ut att vara en fungerande (effektiv) marknad trots att den är förhållandevis ny och stadd i kraftig förändring. Många aktörer gör att konkurrensen är påtaglig i alla led. Det finns konkurrens både på säljarsidan och användarsidan. Dessutom sker viss import och export. Import av pellets är särskilt viktig. Men det sker också import av flis och samt rundved (för flisning). Det finns ett element av regionalisering förknippad med höga transportkostnader för lastbilstransporter.</p> / <p>I discuss various aspects of the market for wood fuels against the background of the increasing importance of bio fuels in the Swedish energy system. The use of bio fuels as a share of total energy supply in Sweden has increased considerably during the last couple of decades. Taxes on fossil fuels explain the increase in use of bio energy. It is district heating (fjärrvärme) which is the main user of wood fuels (outside the paper and sawmill industries themselves).</p><p>The supply chain from the cutting of logs to the end user is described. I base the description/analysis on interviews with suppliers and users of wood fuels as well as secondary sources. Statistics on wood fuels are generally deficient. Prices on wood fuels have increased in real terms and market actors (producers as well as users) expect prices to continue to increase in the medium term.</p><p>The market for wood fuels appears to be an efficient one despite the lack of standards and the despite the fact that it is a “new” market. There are a fairly large number of producers as well as users and there are no barriers to entry. The market is also “contestable” in the sense that wood fuels are imported. There is though an element of regionalisation of the wood fuel market due to high transportation costs.</p>

The swelling mechanisms of U3Si2 under neutron irradiation in reactor conditions are not unequivocally known. The limited experimental evidence that is available suggests that the main driver of the swelling in this material would be fission gases accumulation at crystalline grain boundaries. The steps that lead to the accumulation of fission gases at these locations are multiple and complex. However, gradually, the gaseous fission products migrate by diffusion. Upon reaching a grain boundary, which acts as a trap, the gaseous fission products start to accumulate, thus leading to formation of bubbles and hence to swelling. Therefore, a quantitative model of swelling requires the incorporation of phenomena that increase the presence of grain boundaries and decrease grain sizes, thus creating sites for bubble formation and growth. It is assumed that grain boundary formation results from the conversion of stored energy from accumulated dislocations into energy for the formation of new grain boundaries.This thesis attempts to develop a quantitative model for grain subdivision in U3Si2 based on the above mentioned phenomena to verify the presence of this mechanism and to use in conjunction with swelling codes to evaluate the total swelling of the pellet in the reactor during its lifetime.

Various fuel cycles for a sodium-cooled, subcritical, fast reactor with a fusion neutron source for the transmutation of light water reactor spent fuel have been analyzed. All fuel cycles were 4-batch, and all but one were constrained by a total fuel residence time consistent with a 200 dpa clad and structure materials damage limit. The objective of this study was to achieve greater than 90% burn up of the transuranics from the spent fuel.

Submitted by Elaine Lucia (lucia.elaine@live.com) on 2015-06-26T18:02:33Z No. of bitstreams: 1 Dissertação - Rita Mileni de Souza Lima.pdf: 2126876 bytes, checksum: a214fbd9d08a6c1dcf4fc81b0c2d44db (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-29T14:13:28Z (GMT) No. of bitstreams: 1 Dissertação - Rita Mileni de Souza Lima.pdf: 2126876 bytes, checksum: a214fbd9d08a6c1dcf4fc81b0c2d44db (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-29T14:32:10Z (GMT) No. of bitstreams: 1 Dissertação - Rita Mileni de Souza Lima.pdf: 2126876 bytes, checksum: a214fbd9d08a6c1dcf4fc81b0c2d44db (MD5) / Made available in DSpace on 2015-06-29T14:32:10Z (GMT). No. of bitstreams: 1 Dissertação - Rita Mileni de Souza Lima.pdf: 2126876 bytes, checksum: a214fbd9d08a6c1dcf4fc81b0c2d44db (MD5) Previous issue date: 2010-12-07 / CAPES / Nowadays, Manaus has 175 gas stations, and it is estimated that de lifespan of them, that is around 25 years it is near to the end. This increase the probability of gasoline spills that contains Benzene, Toluene, Methylbenzene and Xylenes (BTEX), and, because of their toxicity and potentially adverse health effects it may become a risk for the general population, if groundwater is contaminated. Hence, the main goal of this study was estimate BTEX exposure through groundwater, as well as the human health risks associated with this exposure. A total of 38 gas stations were visited, and samples of groundwater were taken. Samples were analyzed by gas chromatography fitted with a flame ionization detector (FID), after headspace solid phase microextraction. Human exposure was estimated as a combination of three pathways: inhalation, direct ingestion, and dermal absorption during bath for adult men and women, children and babies. Deterministic and probabilistic risk was assessed. Cancer risk for benzene was estimated in 70% of gas stations from south zone and in 40% from north zone, for all genders and ages. At central-south and west zone, no cancer risk associated with benzene was determined. Cancer risk for benzene was estimated to be between 5xE−05 and 105xE−05 above the limit value of 1xE-05. The children were exposed a higher risks. Non-cancer risk associated with benzene were determined in North and South zones, and associated with xylenes in CentralSouth zone. For probabilistic assessment the 95th percentile of risk was estimated to be 6E−05, indicating that cancer risk is not negligible. Non-carcinogenic risks for toluene, ethylbenzene, and xylenes were lower than the specified level of 1.0. Since health risk associated to BTEX was identified, a monitoring routine need to be implemented by environmental and public health agencies. / Em Manaus existem atualmente 175 postos de gasolina, e estima-se que a vida útil dos tanques de armazenamento de combustíveis desses postos, que é de aproximadamente 25 anos, esteja próxima do final. Assim, aumenta a possibilidade de ocorrência de vazamento ou derramamento de gasolina que contém Benzeno, Tolueno, Etilbenzeno e Xilenos - BTEX, substâncias tóxicas que podem colocar em risco a saúde da população se houver contaminação da água subterrânea, importante fonte de abastecimento domiciliar. Desta forma o objetivo deste trabalho foi avaliar os riscos à saúde humana decorrentes da contaminação da água por BTEX a partir da gasolina provenientes dos postos de revenda de combustíveis da cidade de Manaus. Para isso foi realizado um levantamento dos postos de revenda com poços de água subterrânea, bem como suas condições e tempo de funcionamento. Para quantificação de BTEX na água foram amostrados 38 poços. A análise dos BTEX foi realizada por cromatografia gasosa com detector FID após micro - extração em fase sólida – SPME com headspace. A exposição pela ingestão da água, absorção dérmica e inalação durante o banho foram estimadas para homens, mulheres, crianças e bebês. Foi avaliado o risco de forma determinística e probabilística. Riscos carcinogênicos pela exposição ao benzeno foram encontrados em 70% dos postos na zona sul e 40% da zona Norte para todas as faixas etárias e gêneros. Nas zonas centro-sul, leste e oeste não foram detectados riscos carcinogênicos pela exposição ao benzeno. Nas zonas onde foi encontrado risco de câncer, o mesmo variou de 5 a 10 casos a cada 100.000 habitantes, estando estes valores acima do limite estabelecido de 1 caso para cada 100.000 habitantes. As crianças são o grupo etário exposto a maiores riscos. Em relação aos riscos não carcinogênicos pela exposição aos BTEX, a exposição ao benzeno representou riscos nas zonas norte e sul, e a exposição aos xilenos na zona centro sul. Na avaliação probabilística, o risco carcinogênico para o percentil de 95% da população foi menor que 6 casos por zona, confirmando os dados da avaliação determinística. Os riscos não carcinogênicos com exceção do benzeno, não foram significativos para os demais TEX. Assim, a avaliação indicou riscos à saúde relacionados aos BTEX oriundos de vazamentos de combustíveis de posto de revenda existentes na cidade. As zonas centro-sul, norte e sul são as zonas onde os riscos aos BTEX foram significativos, logo a implantação de uma rotina de monitoramento por parte da agência de controle ambiental bem como da vigilância à saúde se faz necessário, uma vez que o uso da água subterrânea oferece riscos carcinogênicos à população.

In an emerging energy landscape that increasingly discourages the use of traditional fossil fuels, there remain applications for which the continued use of high energy density liquid fuels is required, such as aviation and other uses where space and weight are critical design factors, or long term energy storage where cost and long term availability are required. To achieve this while transitioning to green sources of energy requires the design of next-generation combustion engines that can burn alternative fuels such as bio-derived or synthetic fuels; this process will be heavily dependent on design tools such as computational fluid dynamics packages, underpinned by accurate chemical kinetic models for the fuels in question. These kinetic models often contain thermodynamic information about hundreds of unique chemical species and thousands of chemical reactions forming an interconnected network between species governing their rates of production and destruction. Historically, generation of such high-fidelity kinetic models has required decades of research---too long for the engines that will require advanced fuels. Development of a kinetic model that is predictive of certain quantities of interest (ignition delay times, flame speeds, etc) can broadly be broken into four distinct stages: 1) initial ``crude'' model generation, 2) experimental design, 3) experiments and ab-initio theory calculations, and 4) kinetic model optimization. Advances in data-enabled science and ever-increasing computing power have offered pathways towards eventually automating this process. This work aims to introduce a collection of tools and building blocks that will assist in the overall aim of automatic kinetic model development, and in doing so fill important gaps in the current capabilities available in the literature. In particular, the work here touches on aspects of all four of the stages in the model development process described above. With regard to 1), while there are tools available in the literature for automatic generation of kinetic models for an increasingly large library of fuels, these models remain subject to the constraints imposed by current chemical kinetic model structures and combustion codes. Here, automatic screening procedures are introduced that investigate the impact on kinetic model prediction errors due to two distinct issues related to pressure-dependent chemistry: the lack of a new class of chemical reaction type in current chemical kinetic models, and effects due to how species-specific energy transfer parameters are represented in pressure-dependent stabilization reactions within kinetic models. With regard to 2) and 3), a Bayesian optimal experimental design algorithm is paired with computer-controllable perfectly-stirred reactor experiments with unique capability to both explore a combinatorically complex experiment parameter space (including flowing up to ten unique gas mixtures simultaneously) and measure dozens of chemical species using rapid, on-line diagnostics. This setup allows for key reaction pathways to be carefully "sensitized'' with the addition of trace quantities of key chemical species, a capability that has not been used elsewhere in literature. Generally speaking, other experimental design algorithms in literature have not explored experimental design spaces that are radically different from those used by experienced researchers in their manual experimental design processes, and the complexity of the mixtures explored by most traditional combustion experiments is limited to two or three different chemical species at most. The sensitization of key reaction pathways unlocks the ability to perform truly transformational parameter inferences with minimal amounts of experimental data. With regard to joining step 3) to 4) in the above process, semi-automated post-processing codes allow for rapid optimizations to be performed for a prior kinetic model on the basis of experiments chosen by our experimental design algorithm. Critically, a combination of the experimental design algorithm developed here and the jet-stirred reactor experiments described was tested on the kinetic model for N₂O decomposition, which has uncertainties for key reaction rates that have persisted for decades (indeed, researchers suggest kinetic rate constants for N₂O+O=N₂+O₂ that differ by at least four orders of magnitude!). Optimizations using the Multi-Scale Informatics (MSI) tool developed by our research group were run on the basis of experimental data obtained in the aforementioned experiments, and used to gain insights about the rate constant for a key reaction in N₂O decomposition chemistry, N₂O+O=N₂+O₂ , serving as a proof-of-concept for key portions of what will form the backbone of an automatic kinetic model development pipeline.

Growing prices, limited supply, and public concern about greenhouse gases associated with crude-derived jet fuels have led to development of renewable alternatives which must be compatible with the worldwide civilian and military aviation infrastructure, which were designed for operation with Jet-A/JP-8. Any alternative fuel should not have negative effects on the aircraft engines and fuel systems, especially from a thermal stability perspective, since any adverse effect of the physical properties, and chemical composition, including existence of trace elements, of those fuels may only be revealed after extensive operation, resulting in higher life-cycle maintenance and operation costs. This study considered four types of alternative fuels: two derived by Fischer-Tropsch (FT) process, and two types of Hydro-processing Esters and Fatty acids (HEFA). For each of these types, both raw and 50:50 blends in volume with Jet-A samples have been prepared, thus resulting in eight different fuel blends. Fit-for-purpose ability of these alternative fuels is first investigated by studying the effects of the fuel properties and composition effects on elastomer materials, and micro-turbine performance. When elastomer o-rings, similar to those used in aircraft fuel systems were immersed in renewable fuels, smaller volume change or swelling was detected (lower than 2%), contrary to a 14% swelling observed for baseline Jet-A. Lower swelling may result into leaks during aircraft operation. This trend was reversed when renewable fuels were blended with aromatics containing Jet-A. Lower energetic content per unit volume of the renewable fuels, resulted in a thrust reduction around 10% when compared to baseline Jet-A at full throttle settings, but other than this, no other significant effect on the engine combustion temperature or other parameters were found for short iv duration testing. On the other hand at the end of the alternative fuel testing an injector issue was detected, which caused a localized heat zone at the turbine stator, and subsequent damage. The investigation of the causes of this nozzle fouling, which may be related to fuel contamination, turbine manufacture defects, or operation conditions is left for future studies. Primary focus of this study is coking behavior of 8 different alternative fuel blends over 4 different metallic surfaces, as compared against baseline Jet-A. A specialized single tube heat exchanger apparatus was used where each fuel sample was allowed to flow through a metal tube placed inside a tube furnace. Thermal stresses caused by the break-down of hydrocarbon molecules and the catalytic effects of the tube surfaces affect thermal stability of the fuel, leading to coking deposits under the auto-oxidation and pyrolysis mechanisms. In the results reported in this study, physical methods such as gravimetric measurements were used to obtain the deposits, while UV/VIS absorption, and GC/MS were used to study chemical changes in fuel composition and their relation with coking deposits. Thermal depositions between 16 and 46 μg/cm2 were measured at the tubes after 3 hours of testing, finding no significant differences between the baseline Jet-A and the renewable fuels blends, even when sulfur levels, which are linked to deposits formation, were lower for the renewable fuels. Fuel bulk constituents, such as paraffins and cycloalkanes, under thermal stressing and catalytic influence of the tube metals cracked into reactive intermediates leading to surface deposits formation, like aromatic compounds. These compounds were identified by the shift towards longer excitation wavelengths of the UV-Vis absorption measurements on stressed fuels.